For many years, persons who have lost their natural teeth have used full dentures as functional and aesthetic replacements. The most common configuration has been those dentures which have been individually fitted to a person's upper and lower gum structures as they exist at the time of fitting. When this procedure is carried out by a skillful dentist, with the assistance of a competent dental laboratory, the results can be satisfactory, at least for a time. However, such conventional dentures, which are held in place frictionally (and, to some extent, by suction and sometimes by the supplementary employment of special adhesive powder or paste), often are subject to failure to hold their intended positions. This failure mode, which can increase in frequency as a person's gum structures alter over a period of time, subject the wearer to embarrassment and eventually render the dentures significantly less functional and subject to replacement.
Over the years, dental researchers and innovators have striven to develop other approaches to the replacement of lost natural teeth. For example, individual tooth implants have been successfully carried out, and this procedure is now relatively common. However, this is an uncomfortable, expensive and time consuming process which may not be suitable for many dental patients due to a lack of available bone.
Another process which has been developed employs a series of spaced apart support posts which are individually emplaced into a person's upper and/or lower bony ridge. The support posts (typically eight for each of the maxillary and mandibular positions) depend more or less downwardly from the maxillary bony ridge and more or less upwardly from the mandibular bony ridge. The outward end of each support post typically terminates in a small orb or ball shape. A special denture is prepared which includes a series of openings on its underside. The series of openings are complementarily positioned and dimensioned to receive and frictionally securely engage the orb-shaped end of each support post. The resulting detachable denture system can be very satisfactory.
However, a significant problem with denture systems which employ support posts to engage and hold specially-configured dentures in place is the underlying security of the support posts. There may be, at the time of emplacement or later, insecurity at the bases of the support posts fixed in a patient's bony ridge, notwithstanding the most careful dental work. Similarly, some patients who would otherwise benefit greatly from the emplacement of such a denture system may have insufficient bony ridge structure to receive and securely hold the support post series.
There has been developed an advanced dental technique which may permit those patients who have insufficient bone structure to reliably receive and hold support posts to still enjoy the benefit of detachable dentures or a fixed coupled to such support posts. This technique, which is presently outside the mainstream of dentistry, employs a maxillary and/or mandibular framework emplaced sub-periosteal, but resting on the existing bone structure with the denture support posts depending from a bar carried at the apex of each framework. Implants of this type have had good success, particularly when made in the mandibular position, but are subject to important objections, particularly as used in the maxillary position because of, inter alia, the thinness of the maxillary bone.
One reason for the limited acceptance of sub-periosteal implants is the broad perception that the implant has a high degree of framework strut exposure which is a result of a lack of bone attachment to and around the struts as well as unsatisfactory soft tissue healing. As a result, the implants, particularly in the maxillary position, are subject to infection. It is to an improved dental implant system of this type which alleviates these and other problems to which the present invention is directed.